|
چکیده
|
Understanding the expansion rate history is a primary goal in cosmology. There are various ways to measure the expansion rate at di®erent redshifts and measuring it through the lumi- nosity distance of SNIa is widely used in cosmology. In this work, we split the latest dataset of SNIa (the Pantheon+ sample) into several redshift bins and compute the expansion rate through a non-parametric technique. To do this, we use the Gaussian process to obtain the expansion rate considering data in di®erent redshift bins. For the sake of comparison, we also consider the CDM model and ¯nd the expansion history through an MCMC analysis. Our results indicate that the degeneracy between free parameters prevents a good constraint using the low redshifts data but this is not the case in the GP scenario. Moreover, we study how high redshift SNIa can a®ect the current expansion rate and observe that data at z > 0:5 has almost no impact on the current expansion rate in both approaches.
|